BRENTWOOD — The inmate trusty suspected of breaking into an evidence room to steal heroin while he was left alone at the East Kingston Police Department has a history of theft convictions.

Court documents show Jarred Brisbois, 20, was convicted of stealing a television from a Kingston residence where he was living on Feb. 25, 2010.

Brisbois was also convicted of swiping a laptop computer from a Newton home on March 29, 2010, and jewelry valued in excess of $1,000 from an elderly couple under his care in Atkinson on June 2, 2010.

Brisbois was sentenced to a year in jail and ordered to enter drug and alcohol treatment and counseling.

He eventually served about six months of his sentence before entering a drug treatment facility, according to Rockingham County Attorney James Reams.

But after just one day, Reams said Brisbois left the treatment program and was later sent back to jail for violating probation.

“It’s our belief that the thefts were to finance a drug habit which is part of the reason why we were trying to get him into a drug rehab program,” Reams said.

According to authorities, Brisbois was left alone for several hours on May 11 when he broke into the evidence room and officer’s locker while he was supposed to be washing cruisers. He was among the non-violent inmates given special privileges by being allowed to participate in an inmate trusty program run by the Rockingham County jail.

Deputy County Attorney Tom Reid said Brisbois was brought to the East Kingston Police Department and was supposed to be supervised, but was left alone when an officer went out on patrol.

Brisbois had earned the trust of jail officials and police, but while the officer was away, authorities say he broke into the evidence room where he ingested heroin and smoked marijuana before being returned to the jail under the influence.

Authorities also accuse Brisbois of smuggling heroin and a hypodermic syringe into the jail and sharing the drug with other inmates.

Brisbois also accessed keys to a police cruiser and drove it, but it’s not clear how long he was behind the wheel or where he went.

He is also suspected of breaking into an officer’s locker, where he had access to the officer’s duty belt complete with a gun, Taser, and handcuffs. The officer’s uniform was also hanging in the locker.

Brisbois would have been released this month, but will now remain behind bars until at least November.

He has not yet been charged in connection with the East Kingston break-in as county officials continue to investigate.

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